Proper fluid intake is essential to high-performance athletes and those who exercise for fitness or fun, according to Aric Warren, program director for athletic training at Kansas University.

He recommends that people try to follow guidelines on fluid replacement set by the National Athletic Trainers Assn.

Those guidelines suggest: Two to three hours before exercising, it’s a good idea to drink 20 ounces of water or sports drink. Then, from 10 to 20 minutes before a workout, drink from 7 to 10 ounces of water or sports drink.

During the exercise period itself, people should try to drink from 7 to 10 ounces of fluids every 10-15 minutes.

After exercise, it’s important to replace the body’s fluid losses. People should drink from 20 to 24 ounces of water or sports drink for each pound of body weight that has been lost.

Warren advises against drinking fruit juices or sodas to hydrate the body during exercise, because they aren’t quickly absorbed into the gastrointestinal tract.

Beverages with caffeine can actually dehydrate the body by stimulating excessive urine production, he said.

He recommends using a sports drink like Gatorade, which contains carbohydrates, electrolytes and minerals that are lost during exercise.

Or plain old water.

“That’s a great source (of replenishing fluid),” Warren said.